Carbonized polymer dots/TiO2 photonic crystal heterostructures with enhanced light harvesting and charge separation for efficient and stable photocatalysis

TiO2 photonic crystals (PCs) are widely interesting in photocatalysis due to their slow photon effect for efficient light harvesting. However, their performance is limited by the narrow absorption range and fast charge recombination. In this work, an efficient strategy is developed to enhance the light harvesting and charge lifetime through fabricating TiO2 PC/carbonized polymer dot (CPD) heterostructures. The CPDs with a band gap of 2.08 eV are used to broaden the light absorption range. The energy level of CPDs matches well with TiO2 PCs, forming a type-II heterojunction. The staggered energy levels of CPD/TiO2 PC heterostructures are helpful for charge separation and thus suppressed charge recombination, which is demonstrated by the transient photovoltage (TPV) measurements. Therefore, the CPD/TiO2 PC heterostructures exhibit obviously better photocatalytic performance than individual TiO2 PCs. The combination of CPDs and inorganic semiconductors provides a variety of possibilities for the further development of high-efficiency photocatalysts.